The present invention relates to a method of finishing textile products, and more particularly, to a method of tip shearing tufted carpet utilizing moisture control.
One method of finishing tufted carpet is to tip shear the loop ends to a uniform height. U.S. Pat. No. 4,323,612, which issued in 1982, discusses carpets finished in this manner.
The traditional method of tip shearing carpets involves running tufted carpet over a roller where the roller contacts the polypropylene backing on the bottom of the carpet. The tufted loops are then cut to a uniform height utilizing a cutter having one or more blades which cuts the tufted loops to a uniform height relative to the back of the polypropylene layer on the back of a carpet since the blades of the cutter are a fixed distance from the roller. The greater a distance the tips of the pile extend from the backing, the greater amount is sheared.
The tip-shearing of carpet is utilized to provide a visual effect since the sheared ends provide a different visual effect than non-sheared ends. Furthermore, it has been discovered that the more material which is sheared away (i.e., the shorter lengths the carpet tufts are cut to extend from the backing), the darker most carpets become. Accordingly, if one area is tip sheared to a greater depth than another, the deeper cut area (and thus shorter tufts) are darker than the lighter and taller portions. When darker and lighter portions of the carpet coexist next to each other they typically result in a second quality carpet when uniformity is desired.
Even when attempting to tip shear to a uniform height, the fact that the height is normally cut relative to the back of the polypropylene layer on the back of the carpet as opposed to the lengths of tuft can create problems. Specifically, on some carpet products latex secures the secondary polypropylene to the back of the carpet. If the thickness of the latex layer changes in thickness across its width or length, then it is very likely that a second quality carpet will be produced because the height of the sheared loops will vary according to the change in thickness of the latex layer therebelow.
U.S. Pat. No. 6,035,749 discloses a method of patterned shearing of pile fabrics which effectively utilizes compressed air to provide a particular pattern when utilized in conjunction with an otherwise uniform cutting and severing apparatus. While this reference teaches an excellent way of producing patterns in pile fabrics, it requires the addition of compressed air and jets to be placed proximate to the cutter assembly. This would require retrofitting existing tip shearing cutters with compressed air capability, jets and a controller for the jets.
Accordingly, a need exists to control the tip shearing of carpet for various applications.
A need exists to be able to utilize standard tip shearing cutter equipment while providing a patterned visual effect across the top surface of the carpet having a plurality of heights as measured from the back of the polypropylene backing.
Another need exists for tip-shearing carpet to provide a uniform visual effect even when the latex and/or polypropylene layer thickness is not uniform across the width of the carpet.
Another need exists for selectively tip shearing carpet to at least two depths utilizing an otherwise uniform cutting shearing apparatus.
Another need exists to selectively apply moisture to locations on the carpet to assist in providing a desired multi-height pattern when the moistened carpet portions contact the cutting blade or blades.
Accordingly, a moisture applicator is positioned to apply moisture to a carpet prior to the blades of a tip shearing cutter contacting the carpet so that moisture may be selectively applied for one of a number of purposes such as, but not excluding, creating a pattern, or providing a more uniform appearance as viewed from above in the event that the layer(s) below the carpet are not uniform across the width of the carpet. While moisture application may take one of a variety of forms, the preferred embodiment utilizes a steam applying moisture applicator although liquid could also be applied in other embodiments, such as through liquid jets akin to an ink jet printer, or otherwise. The portions which have moisture applied are cut to a deeper depth than the portions which do not have moisture applied thereto. It is believed that the moisture on the yarn causes more friction with the blades of the shearing apparatus thereby resulting in a deeper cut being made by a normally uniform cutting blade or blades at the selected moistened portion.